mini.clj

(defn permutations [s]
  (lazy-seq
   (if (seq (rest s))
     (apply concat (for [x s]
                     (map #(cons x %) (permutations (remove #{x} s)))))
     [s])))

(defn cost [proposoals s]
  {:permutation s
   :cost (apply + (map-indexed (fn [project candidate-str]
                                          (let [[candidate _]  (clojure.string/split candidate-str #"-")]
                                            (get-in proposoals [candidate project])))
                                        s))})

(defn basic-seq [candidates  max-per]
  (let [opts (range 0 max-per)]
    (flatten (map (fn [c]
                    (map (fn [opt] (str c "-" opt)) opts))
                  candidates))))


(defn mini [proposoals max-per]
  (apply min-key :cost  (map (partial cost proposoals) (permutations (basic-seq (keys proposoals) max-per)))))

(mini  {"c1" [1 2 30 4] "c2" [4 3 200 1]} 2)